Back flow valve

LEAD PIPE

The back flow preventor started to leak through the vent at the bottom. A 1/2" nipple will screw right into the bottom of the vent and stop the leak. Is there any problem with doing this?
Thanks

John

seabee570

backflow preventor leak

It is not a good idea to plug off the vent if that is what you are going to do...if you put a nipple and a cap the,preventor will not funtion as designed....leak, when it is supposed to...probably needs a repair/rebuild kit or you actually have a situation that is causing the unit to leak of as it is suposed to do

LEAD PIPE

What is the vents job? why would it leak and not be a mistake?
thanks

Robert O'Connor_7

BFP

Yes! There IS a problem with this. What kind of heating system do you have? If the answer is steam and the BFP is between the fill valve and the boiler (with no additional valves between it & the boiler) There would be your problem. The boiler is designed to make pressure, when it does, it's pushing the water up to that BRV and the BFP is doing what it's suppose to, PREVENT BACKFLOW. The byproduct of this is material (water & steam) exiting through it's relief port. If the valve was not there and a negetive or vacuum was created in the domestic potable system (In theory) The boiler water could back up into you domestic water supply as well as the public water mains and contaminating both. Although BFP's (especially small residential ones) give us in this industry fits (because of the occational discharging that they so like to do) because of the obvious water & property damage they can cause. Fix it, or replace it, just don't plug it......Robert O'Connor/NJ

LEAD PIPE

boiler

What I dont understand is my water pressure in the boiler is 12psi. The water coming into the house is way more probably 40psi, so how is it going to back flow? I'm not saying I'm not going to fix it if you guys say I need to, I'm just trying to understand.
thanks

John

Dan Peel

Venting

The vent is a "vent to atmosphere". Most of the little backflow preventers will accept very little local corrosion before they start to drip. I find most will vent from the inlet (domestic) pressure side - don't plug it - repair it, replace it or drain it off where you can't see it, but don't plug it. Enjoy....Dan

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Robert O'Connor_7

BFP??

The system, I'll assume it's a forced water boiler by your 12#'s of pressure on your gauge. A water boiler is feed with water through a Pressure Reducing Valve (specially made for a water boiler), this device reduces (or steps down) the pressure from your 40#'s entering your home to the designed system pressure (in most residential aplications) of about 12 - 15#'s of pressure. If in an extreme situation your neighbors house caught on fire and the fire department hooked the hose to the fire hydrant only to discover that there wasn't sufficiant pressure to say spray the water where the fire was, the fire department then hooks that hose to the pumper which sucks the water out of the main and (in theory) your house as well. If a negetive pressure or vacuum existed it could pull the dirty water out of the pressure vessel thus causing contamination if it not been protected by the Back Flow Preventer......Whew!.......Robert O'Connor/NJ

Karis hvac

Which side if the BFP on the street side or Boiler?

And has it been shut off equalizing the pressure in the house and the boiler. This would cause it to leak.

DAVID R. FAUVER

backflow

being a lic. tech. in this field mr. oconner has pretty much said it all. a back flow preventer on a boiler with a vent ( simple backflow ) not a rpz. this device will drip on occastions, it is sensing a pressure differential. if it drips a little here or there it is ok if it runs then it needs to be rebuild. small devices should be replaced every 5 years.

LEAD PIPE

thanks

to all! I will replace it tomorrow.

goodnight

malcolmplumbing106435

back flow leaking

I'm really concerned that a npt nipple can be screwed into a backflow preventer relief valve. The design specs specifically prohibit this. An approved air gap fitting is to be used for piping relief valves to drain. So if you can actually screw a nipple into the relief valve then it is the incorrect device i.e. not an approved backflow preventer and should be replaced What is the mfr and model number of this device?

More to you point often RP backflow's will leak on end of the line applications due to pressure fluctuations in line pressure. When the call for water is over often there is a momentary high backpressure created that might cause an RP to dump. We often will pipe a simple swing check just downstream of the BFP to absorb this shock. A shock absorber would do the same. Of course a dirty, fouled BFP is the most likely problem. A certified tester could resolve this problem with a repair and test
RCPW

Weezbo

Cha ...U Know What?...

don duit.either your fast fill needs a rap or two or the pressure is insufficent on the supply side of the backflow preventor...Two main malfunctions...it is permissable to isolate the two devises with a valve which then requires a estute eye on the subject a couple times a year . the boiler pressure up on heat cant be Flat lined on the pressure side of the pressure temp guage.if it still leaks its Broke:)

Jim Walls

Backflow

John, sounds like you have a Watts 9D-M2, the 1/2" thread is a relief port and the device is recommended for boiler feed lines, either rebuild or replace parts